1. Field of the Invention
The present invention relates generally to attachments for electromechanical driver devices, and more specifically to an attachment for an electromechanical driver device which may be used to staple tissue.
2. Description of the Prior Art
Upon identification of a region of herniated musculature in the abdominal wall, surgical intervention is almost always required. The procedure is straightforward in concept, but includes a number of technically sophisticated features, especially insofar as it is usually carried out remotely, i.e., through small portals formed in the patient""s lower trunk. More particularly, the technique most often utilized involves forming two or three small puncture holes in the lower abdomen of the patient, inserting a corresponding cylindrical tube through each of the holes, passing elongate instruments through the tubes, retracting the soft tissues away from the site of the hernia, and stapling the torn tissue closed. This final closure step often further includes the use of a synthetic mesh, which is placed over the hole for the purpose of supporting the soft tissues and organs disposed above the healing hole. The mesh is stapled directly to the musculature, in the vicinity of the defect. The present invention is directed to the instrumentation which is the stapling component.
Traditional stapling mechanisms function in a simple manner. The staple is initially disposed in a U-shape. The staple driver component contacts the bottom portion of the staple and advances the two upwardly extending prongs of the staple through the items which are to be joined, and toward a stationary anvil portion. Often the items to be coupled require the anvil portion to be disposed behind them to provide adequate support so that the staple prongs may push through. Once the prongs of the staple have advanced through the items to be joined, the prongs contact the anvil. The anvil often comprises staple bending guide grooves formed therein for guiding the plastic deformation of the staples as they advance under the motivation of the staple driver. This plastic deformation bends (or folds) the staples toward one another in order to form the traditional box-shape from the original U-shape. The box-shaped staple is then pulled away from the stapling mechanism by virtue of its being coupled to the items it has joined.
Stapler devices utilized in laparoscopic and endoscopic surgery are significantly different than traditional stapling mechanisms in design and function. Unlike the traditional stapling mechanisms, a spatially distinct and opposing anvil portion is not practical and is therefore not used. Instead, the surgical stapler devices comprise an integrated staple driver and anvil component which holds and advances the staple into and through the tissue to be joined. More particularly, as shown in FIG. 1, the internal surgical tissue stapler devices of the prior art comprise an elongate tube 10 which is designed to slip through the portal tube of the minimally invasive entry hole. The tip 12 of the tube 10 includes a plurality of individual staples which are sequentially engaged by the staple driver. Each staple is initially disposed in a U-shape. The U-shape can be more specifically described by identifying the different regions thereof. The flat bottom portion of the staple has a central portion, and lateral portions. Upwardly extending prongs, which are disposed at the extreme lateral ends of the flat bottom portion, are each approximately equivalent in length, and are approximately equal to one third of the length of the flat bottom portion. The staple driver initially pushes the staple forward by pressing against the bottom portion of the staple at the central portion thereof. The staple is advanced forward until the prongs have extended beyond the tip of the housing, and have penetrated the tissue to be joined. Further advancement of the staple is prevented by an anvil portion which is fixed in the tip of the mechanism. The anvil, unlike the anvil of traditional stapling mechanisms, only contacts the central portion of the bottom portion of the staple, opposite the staple driver. Stated equivalently, once the staple has been advanced fully within the tip of the device, the anvil in the tip prevents the staple from moving forward as it becomes constrained between the staple driver on the back side and the anvil on the front.
At this time, a second mechanism is engaged in order to close the staple. This closing mechanism comprises a pair of straight tines which advance forward from within the tip, and contact the staple at the lateral portions of the bottom flat portion. The continued advancement of the prong bending tines causes the staple to deform as the prongs of the staple are forcibly turned toward one another. However, the actual site of the bending is not along the prongs. It is at the junction of the lateral and central portions of the flat bottom portion. This causes the fully deformed staple in this surgical stapler device to attain a D-shape as opposed to the B-shape which fully deformed staples of traditional stapling mechanisms attain. Release of the staple, once it has been coupled to the joined tissue, is achieved by first retracting the tines which bent the staple, and then twisting the shaft of the device to pull the staple off the anvil.
An additional feature of the surgical stapler devices of the prior art which should be appreciated in light of the present invention is the means by which all of the advancing elements, i.e., the staple driver and the prong bending tines, are motivated. In the minimally invasive surgical stapler devices of the prior art, the elongate tubular portion terminates in a handle which includes a trigger. The trigger has a dual function in that the compression of the trigger initially advances the staple driver without moving the prong bending tines. Once the staple has been fully advanced and is ready for bending, the tines are advanced through the tip to contact the staple, by continued compression of the grip-styled trigger.
It shall be easily recognizable that the requirement of manual triggering, as well as the two-step mechanism for advancing and then forming the staple, are both fraught with potential failures. In addition, the need to twist the shaft of the device to pull the staple off the anvil once the staple has joined the tissue presents a significant risk of tearing tissue as this action stresses both the staple and the tissue.
In addition, another drawback is that the mechanism for discharging the staples is a trigger coupled to a rigid elongate shaft which translates forward and backward in correspondence with the compression and release of the trigger. The rigidity of the shaft requires the surgeon to manipulate the entire device in order to align the stapler properly. Inasmuch as hernias of the abdominal cavity often occur on the floor of the abdomen, this manipulation is often quite difficult.
Finally, with regard to the use of the surgical stapler devices of the prior art, the devices are constructed to be completely disposable. The inability to re-use the devices increases the cost of using the devices. More specifically, this feature does not diminish the overall cost of manufacturing because of the obvious medical use requirements, but does increase the cost per procedure as a new device must be used for each surgery. In fact, if more staples are required for the surgery than are provided for in the device, an entirely new device must be used because there is no possibility of simply replacing the empty staple cartridge.
It is therefore a principal object of the present invention to provide a surgical stapler device which may be easily manipulated into the proper position without having to grossly deform the soft tissues through which the elongate shaft of the device passes.
It is also an object of the present invention to provide a surgical stapler device which has a single-step staple discharging mechanism.
It is a related object of the present invention to provide a surgical stapler device which does not stress surrounding tissue when the staple is released from the tip of the device.
It is an additional object of the present invention to provide a surgical stapler device which does not require the disposal of the tip and the staple driver, thereby minimizing the medical waste and cost associated with the use of the device as compared with surgical stapler devices of the prior art.
Other objects of the present invention shall be recognized in accordance with the description thereof provided hereinbelow, and in the Detailed Description of the Preferred Embodiment in conjunction with the remaining Figures.
The preceding objects of the invention are provided by a stapling attachment of the present invention which is coupleable to and remotely actuateable by an electromechanical driver device. In particular, the attachment couples at a proximal coupling end to a distal end of a flexible drive shaft of the electromechanical driver device, thereby coupling a threaded shaft of the attachment to a flexible draft shaft of the flexible shaft of the electromechanical driver device. As finger triggers actuated on the electromechanical driver device cause the flexible draft shaft to rotate, the threaded shaft rotates and advances in the housing of the attachment a threaded driver element of the attachment which tracks in the housing. Advancement of the threaded driver element advances a staple closing member mounted to the threaded driver element as well as a staple holding member coupled by a spring to the staple closing member. In this manner, a staple carried in a staple carrying groove of a staple carrying element of the staple holding member is advanced toward an opening of a distal staple discharging end of the attachment and into the tissue to be joined. After the staple has penetrated the tissue and the staple holding member contacts an opening lip formed in the opening of the distal staple discharging end, the spring compresses as the staple closing member continues to advance the staple toward the opening. Continued advancement of the staple closing mechanism pushes the staple against a groove lip of the staple carrying groove and protrusion tines of the staple closing member engage lateral portions of the flat bottom portion of the staple to close the prongs of the staple to form a D-shape and thereby join the tissue. Further advancement of the staple closing mechanism causes a sloping surface of the staple closing member to engage the flat bottom portion of the staple to force the staple out of the staple carrying groove to completely discharge and release the staple from the attachment. As finger triggers actuated on the electromechanical driver device cause the flexible draft shaft to reverse rotate, the threaded shaft reverse rotates and retracts the threaded driver element, causing the staple carrying element and the staple holding member to retract within the housing until the staple carrying element is returned to a staple receiving position adjacent a staple cartridge in the housing which contains a plurality of staples. When the staple carrying element is returned to this position, a staple from the plurality of staples is pushed from the staple cartridge into the staple carrying groove by a spring-loaded staple dispenser in functional communication with the staple cartridge, in preparation for a second stapling procedure.
More specifically, referring now to FIG. 2 with respect to the electromechanical driver device, an example embodiment of an electromechanical driver device 50 has a handle 52 and a flexible shaft 54. The handle 52 has a pistol grip-styled design, having a pair of finger triggers 58a,58b which are independently coupled to separate motors 60,62 coupled to and powered by a power source 64 and which each turn separate flexible drive shafts 78a,78b (described more fully hereinbelow). The motors 60,62 are each dual-direction motors, and are also coupled to a manual drive switch 66 mounted to the top of the handle 50, by which the user can selectively alter the turning direction of each motor 60,62. In this example, the power source 64 is a rechargeable battery pack providing a direct current.
The handle 50 further includes (1) a remote status indicator 68; (2) a flexible shaft steering means 70 and (3) an optional additional electrical supply (not shown). The remote status indicator 68 comprises an LCD or similar read-out device by which the user gains knowledge of the position of components (for example, whether the distal staple discharging end of the housing of the stapler attachment is in the proper position prior to the driving of the staples). Second, the handle 50 also includes a manually actuateable steering means 70, for example, a joystick or track ball, for directing the movement of the flexible shaft 72 (described more fully hereinbelow). Finally, the handle 50 may include an additional electrical power supply (not shown) and an on/off switch (not shown) for selectively supplying electrical power to attachments.
More particularly, with respect to the flexible shaft 72, the flexible shaft comprises a tubular sheath 74, preferably formed of a simple elastomeric material which is tissue compatible and which is sterilizable (i.e., is sufficiently rugged to withstand an autoclave). Various lengths of the flexible shaft 72 may be provided in conjunction with the present invention. In such a case, the flexible shaft 72 and the handle 50 should be separable and such that the interface between the proximal end of the flexible shaft 72 and the distal end of the handle 50 includes a coupling means for the drive components. Specifically regarding the drive components of the flexible shaft 72, within the elastomeric sheath are a pair of smaller fixed tubes 76a,76b which each contain a flexible drive shaft 78a,78b which is capable of rotating within the corresponding fixed tube 76a,76b. Each flexible drive shaft 78a,78b itself is capable of translating a torque from the corresponding drive motor 60,62 in the handle 50 to the distal end 80 of the flexible shaft 72, while still being flexible enough to be bent, angled, curved, etc. as the surgeon deems necessary to xe2x80x9csnakexe2x80x9d the flexible shaft 72 through the bowel of the patient. For example, the flexible drive shafts 78a,78b may comprise a woven steel fiber cable. It shall be recognized that other flexible drive shafts may be suitable for this purpose. In order for the distal end 80 of the flexible shaft 72 to couple with an attachment, such as the stapling attachment of the present invention (as described more fully hereinbelow), the distal tips 82a,82b of the flexible drive shafts 78a,78b have a conformation which permits the continued translation of torque. For example, the distal tips 82a,82b of the flexible drive shafts 78a,78b are hexagonal, thereby fitting into a socket, or hexagonal recess, of the proximal coupling end of the housing of the stapler attachment. As suggested above, in conjunction with the manually actuatable steering means 70 mounted to the handle 50, the flexible shaft 72 further includes at least two steering wires 84 which are flexible, but are coupled to the inner surface of the flexible shaft 72 near the distal end 80 thereof. The steering wires 84 may be axially translated relative to one another by actuation of the manually actuatable steering means 70, which action causes the flexible shaft 72 to bend and curve accordingly. Also, as suggested above, in conjunction with the remote status indicator 68 of the handle 50, the flexible shaft 72 further contains an electrical lead 86 for coupling to the attachments. This electrical lead 86 channels a signal from the attachment to the handle 50 for indicating the status of the attachment (for example, indicating whether the tissue to be joined is adjacent to the distal staple discharging end of the stapling attachment, or indicating the number of staples left in the staple cartridge). Similarly, additional electrical leads may be provided to supply power to separate aspects of the attachment if so required.
More particularly, with respect to the stapling attachment of the present invention, the attachment comprises a housing having a distal staple discharging end and a proximal coupling end which has a socket for coupling the attachment to the distal end of the flexible shaft. The distal staple discharging end has an opening through which the staples are sequentially discharged, and an opening lip formed in the opening. The attachment further comprises a threaded shaft which engages the flexible draft shaft of the flexible shaft of the electromechanical driver device when the proximal coupling end is coupled to the distal end of the flexible shaft, such that the threaded shaft rotates in correspondence with the rotation of the flexible draft shaft of the flexible shaft. The threaded shaft has, mounted thereabout, a threaded driver element which is similar in structure to a nut, but which is tracked within the housing so that rotation of the threaded shaft causes the threaded driver element to advance or retract along the threaded shaft within the housing of the attachment.
The attachment further comprises a staple holding member, a staple carrying element integral with said staple holding member, and an anvil portion integral with the staple carrying element. The attachment further comprises a staple closing member concentrically mounted about the staple holding member. The staple holding member and the staple closing member are coupled together by a spring and mounted to the threaded driver element such that advancement of the threaded driver element advances the staple holding member and the staple closing member. The staple closing member comprises a pair of protrusions, or protruding tines which are positioned to engage the staple at the lateral portions of the flat bottom portion of the staple. The staple closing member further comprises a sloped surface which is adapted to engage the central portion of the flat bottom portion of the staple. The staple carrying element comprises an angled staple carrying groove having the anvil portion, or groove lip.
The attachment further comprises a replaceable staple cartridge mounted to the housing of the attachment. The staple cartridge contains a plurality of staples. The staple cartridge is in functional communication with a spring-loaded staple dispenser.
When the proximal coupling end of the housing of the stapling attachment is coupled to the distal end of the flexible shaft of the electromechanical driver device, the threaded shaft of the stapling attachment engages the flexible draft shaft of the flexible shaft. Remote actuation of the flexible draft shaft using a first finger trigger of the electromechanical driver device causes the flexible draft shaft to rotate, which in turn causes the threaded shaft to rotate, which causes the threaded driver element to advance within the housing of the attachment. Alternate remote actuation of the flexible draft shaft using a second finger trigger causes the flexible draft shaft to reverse rotate, which in turn causes the threaded shaft to reverse rotate, which causes the threaded driver element to retract within the housing of the attachment. Thus, as stated above, the staple holding member and the staple carrying element advance and retract with the threaded driver element. When the staple carrying element is retracted into a staple receiving position, adjacent to the staple cartridge, a staple is pushed by the spring-loaded staple dispenser from the staple cartridge into the staple carrying groove of the staple carrying element. As the staple holding member and the staple closing member advance within the housing, the staple is carried within the staple carrying groove. The angle of the staple carrying groove ensures that the staple remains in the staple carrying groove during this advancement. The staple is carried to the distal staple discharging end of the housing and the prongs of the staple are inserted into the tissue to be joined. After the prongs have penetrated the tissue, the opening lip of the distal staple discharging end stops the staple holding member. Upon continued advancement of the threaded driver element, the spring which couples the staple closing member and the staple holding member compresses, causing the staple closing member to further advance. As the staple closing member further advances, the protruding tines engage the staple at the lateral portions of the flat bottom portion of the staple, press the staple against the groove lip of the staple carrying groove, and bend the lateral portions of the flat bottom portion of the staple to close the prongs of the staple to form a D-shape and thereby join the tissue. Upon continued advancement of the threaded driver element, the staple closing member further advances, and the sloped surface of the staple closing member engages the central portion of the flat bottom portion of the staple to force the staple out of the staple carrying groove to completely discharge and release the staple from the attachment. Thereafter, the threaded driver element is retracted, causing the staple carrying element and the staple holding member to retract within the housing. When the staple carrying element is returned to a staple receiving position, adjacent to the staple cartridge, a second staple is pushed by the spring-loaded staple dispenser from the staple cartridge into the staple carrying groove of the staple carrying element in preparation for a second stapling procedure.